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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 | /* UML hardware watchdog, shamelessly stolen from:
*
* SoftDog 0.05: A Software Watchdog Device
*
* (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
* http://www.redhat.com
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
* warranty for any of this software. This material is provided
* "AS-IS" and at no charge.
*
* (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk>
*
* Software only watchdog driver. Unlike its big brother the WDT501P
* driver this won't always recover a failed machine.
*
* 03/96: Angelo Haritsis <ah@doc.ic.ac.uk> :
* Modularised.
* Added soft_margin; use upon insmod to change the timer delay.
* NB: uses same minor as wdt (WATCHDOG_MINOR); we could use separate
* minors.
*
* 19980911 Alan Cox
* Made SMP safe for 2.3.x
*
* 20011127 Joel Becker (jlbec@evilplan.org>
* Added soft_noboot; Allows testing the softdog trigger without
* requiring a recompile.
* Added WDIOC_GETTIMEOUT and WDIOC_SETTIMOUT.
*/
#include <linux/module.h>
#include <linux/config.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/reboot.h>
#include <linux/smp_lock.h>
#include <linux/init.h>
#include <asm/uaccess.h>
#include "mconsole.h"
MODULE_LICENSE("GPL");
/* Locked by the BKL in harddog_open and harddog_release */
static int timer_alive;
static int harddog_in_fd = -1;
static int harddog_out_fd = -1;
/*
* Allow only one person to hold it open
*/
extern int start_watchdog(int *in_fd_ret, int *out_fd_ret, char *sock);
static int harddog_open(struct inode *inode, struct file *file)
{
int err;
char *sock = NULL;
lock_kernel();
if(timer_alive)
return -EBUSY;
#ifdef CONFIG_HARDDOG_NOWAYOUT
__module_get(THIS_MODULE);
#endif
#ifdef CONFIG_MCONSOLE
sock = mconsole_notify_socket();
#endif
err = start_watchdog(&harddog_in_fd, &harddog_out_fd, sock);
if(err) return(err);
timer_alive = 1;
unlock_kernel();
return nonseekable_open(inode, file);
}
extern void stop_watchdog(int in_fd, int out_fd);
static int harddog_release(struct inode *inode, struct file *file)
{
/*
* Shut off the timer.
*/
lock_kernel();
stop_watchdog(harddog_in_fd, harddog_out_fd);
harddog_in_fd = -1;
harddog_out_fd = -1;
timer_alive=0;
unlock_kernel();
return 0;
}
extern int ping_watchdog(int fd);
static ssize_t harddog_write(struct file *file, const char *data, size_t len,
loff_t *ppos)
{
/*
* Refresh the timer.
*/
if(len)
return(ping_watchdog(harddog_out_fd));
return 0;
}
static int harddog_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg)
{
static struct watchdog_info ident = {
WDIOC_SETTIMEOUT,
0,
"UML Hardware Watchdog"
};
switch (cmd) {
default:
return -ENOTTY;
case WDIOC_GETSUPPORT:
if(copy_to_user((struct harddog_info *)arg, &ident,
sizeof(ident)))
return -EFAULT;
return 0;
case WDIOC_GETSTATUS:
case WDIOC_GETBOOTSTATUS:
return put_user(0,(int *)arg);
case WDIOC_KEEPALIVE:
return(ping_watchdog(harddog_out_fd));
}
}
static struct file_operations harddog_fops = {
.owner = THIS_MODULE,
.write = harddog_write,
.ioctl = harddog_ioctl,
.open = harddog_open,
.release = harddog_release,
};
static struct miscdevice harddog_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &harddog_fops,
};
static char banner[] __initdata = KERN_INFO "UML Watchdog Timer\n";
static int __init harddog_init(void)
{
int ret;
ret = misc_register(&harddog_miscdev);
if (ret)
return ret;
printk(banner);
return(0);
}
static void __exit harddog_exit(void)
{
misc_deregister(&harddog_miscdev);
}
module_init(harddog_init);
module_exit(harddog_exit);
/*
* Overrides for Emacs so that we follow Linus's tabbing style.
* Emacs will notice this stuff at the end of the file and automatically
* adjust the settings for this buffer only. This must remain at the end
* of the file.
* ---------------------------------------------------------------------------
* Local variables:
* c-file-style: "linux"
* End:
*/
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